Table 2.

Diseases associated with respiratory microbiome dysbiosis.

Disease	Microbiome Change	Functional Effect	Ref.
Asthma	Bacteroides spp. ↓ Haemophilus, Moraxella, Streptococcus, Staphylococcus ↑	Loss of immune regulation, steroid resistance, neutrophilic inflammation, and increased risk of exacerbation	[69]
	Lactobacillales, Mogibacteriaceae, Veillonella, Prevotella ↓ M. catarrhalis, H. influenzae, Streptococcus spp. ↑	Neutrophilic inflammation, steroid resistance, impaired immune regulation (IL-5, IL-6, IL-13, IL-8, IL-17A ↑ )	[71, 72]
	Firmicutes, Bacteroidetes, Actinobacteria ↓ Proteobacteria ↑	Reduced microbial diversity, impaired lung function, and a shift toward a proinflammatory microbial profile	[73]
COPD	Prevotella, Veillonella, Gemella ↓ Haemophilus, Moraxella, S. pneumoniae, S. aureus, P. aeruginosa, gram-negative enteric bacteria ↑	Neutrophilic inflammation, reduced lung function, immune exhaustion, and decreased microbial diversity (IL-8, TNF, IL-1β ↑ )	[75]
	Prevotella, Veillonella ↓ H. influenzae, S. pneumoniae, M. catarrhalis ↑	Biofilm-mediated immune evasion, persistent neutrophilic inflammation, and reduced antibiotic responsiveness	[76]
Respiratory Infections	Prevotella, Veillonella, Rothia spp. ↓ H. influenzae, S. pneumoniae, M. catarrhalis ↑	Reduced diversity, immune imbalance, and increased susceptibility to symptomatic viral infection	[81]
	Prevotella, Veillonella ↓ H. influenzae, M. catarrhalis, S. pneumoniae ↑	Impaired mucosal immunity, increased susceptibility to viral and bacterial coinfection	[82, 83]
	Corynebacterium, Dolosigranulum ↓	Negative correlation with disease severity, IFN-γ, IL-33 ↓	[84]